Clinical and neurophysiological risk factors of learning disabilities in different types of idiopathic focal epilepsy

Objectives Academic difficulties are common in epileptic children. A learning disability (LD) is a reduction in the learning capacity of children or the intellectual ability of adults, which is different from mental retardation or dementia. Materials & Methods The participants were 56 patients, of whom 35 were males (62.5%), and 21 were females (37.5%). The participants attended the Neurology Outpatient Clinic, the Sohag University Hospital, between December 2016 and May 2017. Children with chronological age between 7 and 16 years with idiopathic focal and normal mental and motor developmental history were enrolled in this cross-sectional study. The Revised Quick Neurological Screening Test was used to assess different types of LD. Results LDs were present in 67.9% of our participants with a statistically significant association between LDs in one arm and younger age, earlier age of onset of epilepsy, frequent seizures, and seizure semiology, particularly of temporal lobe origin, in the other arm. In addition, left epileptic focus on EEG, prolonged treatment duration with antiepileptic drugs (AED), and polytherapy were significantly correlated with LDs. Conclusion Many factors are significantly correlated with LDs in children with idiopathic focal epilepsy, like age of the patient, age of epilepsy onset, seizure semiology, prolonged AED treatment, and polytherapy.


Introduction
As a common neurological condition, epilepsy can occur at any age, with a point prevalence of active epilepsy being 6.38 per 1,000 persons (1). For the diagnosis of epilepsy, at least two unprovoked seizures are required 24 hours apart, or one unprovoked with a high risk of recurrence (2,3). Focal epilepsy is classified according to the presence or absence of awareness, associated motor behavior (motor and non-motor), and focal to bilateral tonic-clonic seizures (4,5). A learning disability is a type of neurodevelopmental disorder that impedes the capacity to learn or use specific academic skills (e.g., reading, writing, or arithmetic) during the early years of education (6).
Academic difficulties, particularly in arithmetic, spelling, and reading, are common in epileptic children (7,8).
It was also documented that learning problems were more prevalent in children with focal epilepsy than in those with generalized epilepsy and in symptomatic syndromes compared with idiopathic or cryptogenic ones (9)(10)(11)(12).

The Quick Neurological Screening Test (QNST)
is a neuropsychological test for screening learning disorders (13). The majority of the previous studies use IQ as an indicator of learning disabilities, and most of them enroll patients with both focal epilepsies (including idiopathic and symptomatic) and generalized epilepsies. This cross-sectional study aimed to investigate the effect of clinical and neurophysiological risk factors of LDs on idiopathic focal epilepsy.
Uncontrolled seizures are defined as more than two changes in AED therapy and then ≥1 epilepsy-related emergency department (ED) visit/ hospitalization within one year, while controlled seizures are defined as no AED change and no epilepsy-related ED visit/hospitalization (15,16

Results
The study included 56 patients (

Results
The study included 56 patients (

Subtest Description l. Hand skill
The subject is instructed to write his or her name and an age-appropriate six-to eightword simple sentence.

Figure recognition and production
Present page containing a series of five geometric figures on the recording form. The subject is instructed to name each one and then draw them.

Palm form recognition
Subject is instructed to identify, solely by touch, numerals drawn on the palm of his or her hands.

Eye tracking
Present a pencil or other appropriate object at Subject 's eye level. The subject is instructed to follow it back and forth.

Sound patterns
The subject is instructed to reproduce sound patterns with the eyes closed manually and orally after the patterns are demonstrated by the examiner.

Finger to nose
Subject is instructed to close both eyes and reach back and forth between examiner's hand and the tip of his or her own nose.

Thumb and finger circle
The subject is instructed to form successive circles by touching the thumb to each of the fingers.

Double simultaneous stimulation of hand and
cheek Examiner observes whether subject is able to feel the gentle simultaneous touch on both hands, bilateral cheeks, and one hand and the contralateral cheek.

Rapidly reversing repetitive hand movements
The subject is instructed to turn his or her hands over rapidly and repetitively after these movements are demonstrated by the examiner.

Arm and leg extension
The subject is instructed to extend his or her extremities in front of him or her as straight as possible in sitting position.

I l. Tandem walk
The subject is instructed to walk a straight line for at least 10 feet, placing the heel of each shoe directly against the toe of the opposite foot. Subject then walk backward on the "line", heel-to-toe, and then repeats the tandem walk forward with his or her eyes closed.

Stand on one leg
The subject is instructed to balance himself or herself with the eyes open and closed on each foot for a count of 10 seconds.

Skip
Subject is instructed to skip across the room.

Left-right discrimination
This section is scored from parts of three other subtests (6,7,12).
The left-right discrimination is determined by observing whether subjects hold up the right hand (leg) when E uses the right hand (leg) to demonstrate.

Behavioral irregularities
The final item requires general observation of subject's behavior (E.g., excessive talking, fidgeting, distractibility, defensiveness, anxiety, etc.) during the entire test.

Discussion
Epilepsy is an important health problem affecting more than 50 million people worldwide (22,23).
School underachievement is more common in children with epilepsy (19), and more than 60% of patients suffer from school-related difficulties (20). This study demonstrated that the younger age of children was significantly associated with LDs, and this result is similar to that obtained from several studies (12,23,24). However, this finding is not similar to that obtained in other studies (19,20) in which children with generalized and focal epilepsies were enrolled and different tests, namely the Bender test and the teacher report, were used to assess school achievements.
The current study demonstrated that earlier age of epilepsy onset was significantly associated with LDs, which is in accordance with the results obtained by Schoenfeld et al. (25), who affirmed that a patient's age was strongly correlated with the academic performance in children with epilepsy. In addition, Zelnik et al. (9) documented that young age at onset was among the predictors for special education for epileptic kids. Also, Huttenlocher et al. (26) revealed that cognitive impairment was worse in epilepsy during early development than in the mature brain. This finding is clarified in some animal studies reporting that early seizures may profoundly impact the development of the maturing brain (27)(28)(29). Furthermore, the immature brain is more inclined to seizures than is the mature brain because of an imbalance between excitation and inhibition mechanisms and various physiologic and structural features (30,31). Other studies failed to find a significant relationship between LDs and young age at the onset because of different sample sizes and the enrollment of all children with epilepsy, and not an idiopathic focal one, as we recruited (19,20,(32)(33)(34).
We found that LDs were significantly correlated with frequent seizures, and this finding is confirmed by previous studies reporting that poor seizure control appears to be associated with decreased academic performance, particularly reading achievement and attention problems (9,12,34 Still, these results need to be confirmed in a more extensive and detailed study.

Acknowledgement
The study was approved by the local Ethical Committee of Sohag Faculty of Medicine, Sohag University 3/ 2015. Consent to participate: Informed written (when available) consent was obtained from all patients (or their relatives) for participation and publication of this study.